Anaemia, commonly defined as a haemoglobin level of <14g/dl in men and <12g/dl in women, occurs in over 30% of cancer patients at any point in time, and its incidence increases with treatment and disease progression. This anaemia could be related to the patient (haemoglobinopathies, gastrointestinal problems, thalassemia, etc.), related to the disease (bone marrow infiltration, bowel resection, hypersplenism, diminished nutritional state) or related to therapy (drug-induced haemolysis, hypoplasia of bone marrow-bearing areas such as the pelvis secondary to radiotherapy, bone marrow and renal toxicity secondary to chemotherapy, etc.). Inflammatory cytokines such as tumour necrotic factor-alpha and interleukin-6, among others, play a major role in the pathophysiology of anaemia in the cancer patient, not only through complex mechanisms of the purely inflammatory situation but also through genetic regulatory aspects of erythropoiesis.